Safety pipette



July 1947- E. L. BRADY ET AL 2,423,173

. SAFETY PIPETTE Filed March 30, 1945 INVENTOIK Patented 1, 1947 SAFETY PIPE'I'IE Edward L. Brady and Lawrence E. Glendenin,

Oak Ridge, Tenn,

assigllors to United States of America, as represented by the Director of the Oflice of Scientific Research and Development, Ofice for Emergency Management Application March 30, 1945, Serial No. 585,7ii6

This invention relates to pipettes and particularly to structural features of pipettes adapted to user to draw liquid into his mouth which result is very undesirable, especially when the liquid is corrosive or radioactive.

An object of the invention is to provide a pipette construction which will prevent inadvertent flooding of the mouth of the user.

Other objects and advantages of the invention will be evident from the following description when read in connection with the accompanying drawing the single figure of which shows in perspective a pipette incorporating the invention. The pipette as shown consists of a suitable intake tube in which may have a calibration mark I I, a mouthpiece l 2 and an intermediate enlarged portion l3 having a part of the wall tom away to show a wall member ii. In accordance with the invention the wall it is pervious to air, but when wet is not pervious, at least under pressure differences which can be provided by oral suction by laboratory workers. ably consists of a sintered glass disc sealed in the portion It. and the medium grade disc manufac- The wall I prefertured by Corning has been found to ,be quite'satisfactory. Inasmuch as the primary function of the wall is to prevent sudden rushes of-liquid to the mouthpiece i2 and need not provide anabsolute barrier to the passage of a liquid, it will the barrier member is a thin 2 Claims; (Cl. 222-189) 2 be evident that the porosity of the wall It may vary considerably and still perform its protective function.

It will be understood that the invention is not limited in its application to the particular pipette illustrated.

We claim:

1. A pipette adapted to pick up liquid by oral suction comprising a tubular member open at both ends and having an'enlarged portion intermediate said ends, and a barrier member within said enlarged portion and having its periphery secured to the wall of said tubular member, said barrier member being pervious to air when .dry and impervious to air and liquid when wet.

2. A pipette as claimed in claim 1 in which disc of sintered EDWARD L. BRADY. LAWRENCE E. GLENDENDJ'.

REFERENCES CITED The following references are of record in the glass.

file of this patent: I

25 UNITED STATES PATENTS Number Name Date 2,376,231 Cohn May 15, 1945 2,114,748 Prausnitz Apr, 19, 1938 Luertzing Nov. 8,1938 

